Field of the Invention
The present invention relates to a sealing resin composition, and particularly relates to a sealing resin composition that can be preferably used for sealing an organic EL element and the like.
Discussion of the Background
Organic EL (Electroluminescence) element is a material attracting attention in recent years, which is a luminescence element using an organic substance as a luminescence material and capable of providing high-intensity luminescence at a low voltage. However, since organic EL element is extremely weak to the moisture, the organic material itself is altered by the moisture, problems occur in that the brightness decreases, luminescence is not produced, the interface between the electrode and the organic EL layer is detached due to an influence of moisture, and the metal is oxidized to be highly resistant.
When a thermoset resin composition is used as an entire surface-sealing material, advantages are that the lamination operation is easy since the material viscosity before curing is low, and the resistance to moisture permeability of the cured product after heat curing is high. On the other hand, however, a problem occurs in that the organic EL element is degraded due to the heating temperature during heat curing. In addition, since the light is blocked by a getter agent layer incorporated for the purpose of dehydration in a sealing space in conventional can sealing structures, the efficiency of light emission from the sealing face is defectively poor. However, an advantage of highly efficient emission of luminescence from the sealing face side can be afforded by a structure wherein the entire surface is sealed with a resin composition. In this case, the sealing material is required to be transparent to afford high emission efficiency.
As a method for avoiding heat deterioration of an organic EL element, patent document 1 discloses a resin composition containing a polyisobutylene resin, a polyisoprene resin and/or a polyisobutylene resin having a functional group capable of reaction with an epoxy group, a tackifier resin, and an epoxy resin. However, transparency is not referred to, and sufficient study has not been conducted.